CVE-2026-33693

CVE-2026-33693: SSRF via 0.0.0.0 Bypass no activitypub-federation-rust v4isinvalid CVSS 6.5 Moderado Palavras-chave: SSRF, 0.0.0.0, bypass de validação de IP, activitypub-federation, Lemmy, Rust, ActivityPub Índice Overview Vulnerability Details Technical Analysis Attack Chain Impact Remediation...

cve-2026-47777

CVE-2026-47777 — Mastodon फ़ीचर्ड कलेक्शन प्राधिकरण बाईपास अवलोकन मैंने एक उच्च गंभीरता प्राधिकरण बाईपास भेद्यता की जिम्मेदारी से खुलासा किया जो Mastodon के प्रयोगात्मक फ़ीचर्ड कलेक्शन संघीय पाइपलाइन को प्रभावित करती है। CVE ID: CVE-2026-47777 प्रभावित घटक ActivityPub::VerifyFeaturedItemService...

CVE-2026-54740

Lemmy is a link aggregator and forum for the fediverse. Prior to 0.19.19 and 1.0.0-alpha.18, a lower-ranked remote moderator can remove a higher-ranked moderator by sending a signed ActivityPub Remove activity to the target instance. The local API uses LocalUser::ishighermodoradmincheck to enforc...

CVE-2026-54740 Lemmy: Lower-ranked federated moderator can remove higher-ranked moderators

Lemmy is a link aggregator and forum for the fediverse. Prior to 0.19.19 and 1.0.0-alpha.18, a lower-ranked remote moderator can remove a higher-ranked moderator by sending a signed ActivityPub Remove activity to the target instance. The local API uses LocalUser::ishighermodoradmincheck to enforc...

CVE-2026-54740

In Lemmy versions prior to 0.19.19 and 1.0.0-alpha.18, the federated ActivityPub handler CollectionRemove::receive in crates/apub/activities/src/community/collection_remove.rs omits the rank check (is_higher_mod_or_admin_check) enforced by the local API, allowing any signed ActivityPub Remove act...

EUVD-2026-62844

Lemmy is a link aggregator and forum for the fediverse. Prior to 0.19.19 and 1.0.0-alpha.18, a lower-ranked remote moderator can remove a higher-ranked moderator by sending a signed ActivityPub Remove activity to the target instance. The local API uses LocalUser::ishighermodoradmincheck to enforc...

CVE-2026-54740 Lemmy: Lower-ranked federated moderator can remove higher-ranked moderators

Lemmy is a link aggregator and forum for the fediverse. Prior to 0.19.19 and 1.0.0-alpha.18, a lower-ranked remote moderator can remove a higher-ranked moderator by sending a signed ActivityPub Remove activity to the target instance. The local API uses LocalUser::ishighermodoradmincheck to enforc...

CVE-2026-54742 Lemmy: `CollectionAdd::Featured` does not check the post is in the community

Lemmy is a link aggregator and forum for the fediverse. From 0.19.18 until 0.19.19 and 1.0.0-alpha.20, a community moderator can feature or unfeature posts in other communities through federated CollectionAdd and CollectionRemove activities using CollectionType::Featured. After verifymodaction...

PT-2026-78675

Name of the Vulnerable Software and Affected Versions Lemmy versions prior to 0.19.19 Lemmy versions prior to 1.0.0-alpha.18 Description A lower-ranked remote moderator can remove a higher-ranked moderator by sending a signed ActivityPub Remove activity to the target instance. While the local API...

PT-2026-78677

Name of the Vulnerable Software and Affected Versions Lemmy versions 0.19.18 through 0.19.18 Lemmy versions 1.0.0-alpha.1 through 1.0.0-alpha.19 Description A community moderator can feature or unfeature posts belonging to other communities. This occurs during federated CollectionAdd and...

BIT-MASTODON-2026-72916 Mastodon: SSRF Protection Bypass via IPv4-compatible IPv6 Addresses

Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.4.21, 4.5.14, 4.6.4, and 4.7.0, PrivateAddressCheck.privateaddress? in app/lib/privateaddresscheck.rb normalized IPv4-mapped IPv6 addresses but did not recognize IPv4-compatible IPv6 addresses with...

BIT-MASTODON-2026-72914 Mastodon: Exhausting data by an unauthenticated request to the admin retention API

Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.4.21, 4.5.14, 4.6.4, and 4.7.0, the administrative statistics endpoints handled by Api::V1::Admin::MeasuresController and Api::V1::Admin::RetentionController checked authorization only after beginning expensive...

CVE-2026-73038

NodeBB before 4.15.0 contains a stored cross-site scripting vulnerability in the renderEmoji function that fails to escape tag.icon.url and tag.name attributes. Attackers can deliver malicious ActivityPub Create/Note objects with crafted emoji tags to inject arbitrary HTML and JavaScript into...

EUVD-2026-58226

NodeBB before 4.15.0 contains a stored cross-site scripting vulnerability in the renderEmoji function that fails to escape tag.icon.url and tag.name attributes. Attackers can deliver malicious ActivityPub Create/Note objects with crafted emoji tags to inject arbitrary HTML and JavaScript into...

CVE-2026-73038 NodeBB < 4.15.0 Stored XSS via ActivityPub emoji tag.icon.url and tag.name

NodeBB before 4.15.0 contains a stored cross-site scripting vulnerability in the renderEmoji function that fails to escape tag.icon.url and tag.name attributes. Attackers can deliver malicious ActivityPub Create/Note objects with crafted emoji tags to inject arbitrary HTML and JavaScript into...

CVE-2026-73038

NodeBB before 4.15.0 contains a stored cross-site scripting vulnerability in the renderEmoji function that fails to escape tag.icon.url and tag.name attributes. Attackers can deliver malicious ActivityPub Create/Note objects with crafted emoji tags to inject arbitrary HTML and JavaScript into...

CVE-2026-73038 NodeBB < 4.15.0 Stored XSS via ActivityPub emoji tag.icon.url and tag.name

NodeBB before 4.15.0 contains a stored cross-site scripting vulnerability in the renderEmoji function that fails to escape tag.icon.url and tag.name attributes. Attackers can deliver malicious ActivityPub Create/Note objects with crafted emoji tags to inject arbitrary HTML and JavaScript into...

CVE-2026-73038

NodeBB before 4.15.0 contains a stored XSS in the renderEmoji function due to failed escaping of tag.icon.url and tag.name within ActivityPub emoji tags. Attackers can send crafted Create/Note objects to inject HTML/JS into stored post content, leading to code execution in viewers’ browsers. Impa...

CVE-2026-73211

PeerTube is an ActivityPub-federated video streaming platform. Prior to 8.1.6, ActorFollowModel.updateScore interpolates the attacker-controlled ActivityPub actor inboxUrl into an SQL query, allowing an unauthenticated remote server to read and write PeerTube database tables, including...

CVE-2026-73090

PeerTube is an ActivityPub-federated video streaming platform. Prior to 8.2.2, processUpdateActivity and processUpdateVideo accept an ActivityPub Update containing a Video object without verifying that byActor.url is authorized for the host in videoObject.id, allowing a malicious federated server...